WoW reads your hard-drive
In the past WoW's Warden functions could be checked by third party gamer software which could make sure that it did not get out of control.
However the latest Warden patch includes a different random cryptographic hash function in every copy, apparently used for cryptographic key exchange.
This makes it impossible for the third party software to work and, according to Onwarden, is a security hole in its own right. A hacker, or even Blizzard itself, could use it to retrieve information from a computer at random.
All it would take is for Blizzard, or a rogue employees to decide to have a look at a punter's computer and they could do it.
The fact that the new Warden patch makes it impossible for third party software to see what Blizzard is up to means that it is almost impossible for users to tell what is going on.